Figure 4.
Individual-study-data meta-analysis (IDA)-derived accuracy of urine and plasma neutrophil gelatinase-associated lipocalin (NGAL) level for prediction of the study end points, (A) acute kidney injury (AKI), (B) severe AKI, and (C) AKI requiring dialysis (AKI-D) illustrated as summed receiver operator characteristic (sROC) curves (red curve) and individual ROC curves (grey) grouped by sample material. Numbers illustrate the area under the ROC curve (AUC) and 95% CI. The 3 pairs of sensitivity and specificity (95% sensitivity, optimal combination of sensitivity and specificity, and 95%specificity) of 1 individual study are connected by a line. Specifically, the sROC curves for AKI are derived from 12 studies regarding urine NGAL and 18 studies for plasma NGAL; for severe AKI, 10 studies regarding urine NGAL and 16 studies regarding plasma NGAL; for AKI-D, the sROC curve is derived from 9 individual ROC curves for urine NGAL and 12 regarding plasma NGAL (Table 1). Abbreviation: RRT, renal replacement therapy.